Enable PowerShell Remoting... Remotely

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##
## Enable-RemotePsRemoting
##
## From Windows PowerShell Cookbook (O'Reilly)
## by Lee Holmes (http://www.leeholmes.com/guide)
##
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<#

.SYNOPSIS

Enables PowerShell Remoting on a remote computer. Requires that the machine
responds to WMI requests, and that its operating system is Windows Vista or
later.

.EXAMPLE

PS > Enable-RemotePsRemoting <Computer>

#>

param(
    ## The computer on which to enable remoting
    $Computername,

    ## The credential to use when connecting
    $Credential = (Get-Credential)
)

Set-StrictMode -Version 3

$VerbosePreference = "Continue"

$credential = Get-Credential $credential
$username = $credential.Username
$password = $credential.GetNetworkCredential().Password

$script = @"

`$log = Join-Path `$env:TEMP Enable-RemotePsRemoting.output.txt
Remove-Item -Force `$log -ErrorAction SilentlyContinue
Start-Transcript -Path `$log

## Create a task that will run with full network privileges.
## In this task, we call Enable-PsRemoting
schtasks /CREATE /TN 'Enable Remoting' /SC WEEKLY /RL HIGHEST ``
    /RU $username /RP $password ``
    /TR "powershell -noprofile -command Enable-PsRemoting -Force" /F |
    Out-String
schtasks /RUN /TN 'Enable Remoting' | Out-String

`$securePass = ConvertTo-SecureString $password -AsPlainText -Force
`$credential =
    New-Object Management.Automation.PsCredential $username,`$securepass

## Wait for the remoting changes to come into effect
for(`$count = 1; `$count -le 10; `$count++)
{
    `$output = Invoke-Command localhost { 1 } -Cred `$credential ``
        -ErrorAction SilentlyContinue
    if(`$output -eq 1) { break; }

    "Attempt `$count : Not ready yet."
    Sleep 5
}

## Delete the temporary task
schtasks /DELETE /TN 'Enable Remoting' /F | Out-String
Stop-Transcript

"@

$commandBytes = [System.Text.Encoding]::Unicode.GetBytes($script)
$encoded = [Convert]::ToBase64String($commandBytes)

Write-Verbose "Configuring $computername"
$command = "powershell -NoProfile -EncodedCommand $encoded"
$null = Invoke-WmiMethod -Computer $computername -Credential $credential `
    Win32_Process Create -Args $command

Write-Verbose "Testing connection"
Invoke-Command $computername {
    Get-WmiObject Win32_ComputerSystem } -Credential $credential